1 files changed, 102 insertions, 0 deletions
diff --git a/game/shared/ray_dda.cc b/game/shared/ray_dda.cc
new file mode 100644
index 0000000..132d05a
--- /dev/null
+++ b/game/shared/ray_dda.cc
@@ -0,0 +1,102 @@
+#include "shared/pch.hh"
+#include "shared/ray_dda.hh"
+
+#include "shared/coord.hh"
+#include "shared/dimension.hh"
+
+RayDDA::RayDDA(const Dimension *dimension, const chunk_pos &start_chunk, const glm::fvec3 &start_fpos, const glm::fvec3 &direction)
+{
+    reset(dimension, start_chunk, start_fpos, direction);
+}
+
+RayDDA::RayDDA(const Dimension &dimension, const chunk_pos &start_chunk, const glm::fvec3 &start_fpos, const glm::fvec3 &direction)
+{
+    reset(dimension, start_chunk, start_fpos, direction);
+}
+
+void RayDDA::reset(const Dimension *dimension, const chunk_pos &start_chunk, const glm::fvec3 &start_fpos, const glm::fvec3 &direction)
+{
+    this->dimension = dimension;
+    this->start_chunk = start_chunk;
+    this->start_fpos = start_fpos;
+    this->direction = direction;
+
+    this->delta_dist.x = direction.x ? cxpr::abs(1.0f / direction.x) : std::numeric_limits<float>::max();
+    this->delta_dist.y = direction.y ? cxpr::abs(1.0f / direction.y) : std::numeric_limits<float>::max();
+    this->delta_dist.z = direction.z ? cxpr::abs(1.0f / direction.z) : std::numeric_limits<float>::max();
+
+    this->distance = 0.0f;
+    this->vpos = coord::to_voxel(start_chunk, start_fpos);
+    this->vnormal = voxel_pos(0, 0, 0);
+
+    // Need this for initial direction calculations
+    auto lpos = coord::to_local(start_fpos);
+
+    if(direction.x < 0.0f) {
+        this->side_dist.x = this->delta_dist.x * (start_fpos.x - lpos.x);
+        this->vstep.x = voxel_pos::value_type(-1);
+    }
+    else {
+        this->side_dist.x = this->delta_dist.x * (lpos.x + 1.0f - start_fpos.x);
+        this->vstep.x = voxel_pos::value_type(+1);
+    }
+
+    if(direction.y < 0.0f) {
+        this->side_dist.y = this->delta_dist.y * (start_fpos.y - lpos.y);
+        this->vstep.y = voxel_pos::value_type(-1);
+    }
+    else {
+        this->side_dist.y = this->delta_dist.y * (lpos.y + 1.0f - start_fpos.y);
+        this->vstep.y = voxel_pos::value_type(+1);
+    }
+
+    if(direction.z < 0.0f) {
+        this->side_dist.z = this->delta_dist.z * (start_fpos.z - lpos.z);
+        this->vstep.z = voxel_pos::value_type(-1);
+    }
+    else {
+        this->side_dist.z = this->delta_dist.z * (lpos.z + 1.0f - start_fpos.z);
+        this->vstep.z = voxel_pos::value_type(+1);
+    }
+}
+
+void RayDDA::reset(const Dimension &dimension, const chunk_pos &start_chunk, const glm::fvec3 &start_fpos, const glm::fvec3 &direction)
+{
+    reset(&dimension, start_chunk, start_fpos, direction);
+}
+
+voxel_id RayDDA::step(void)
+{
+    if(side_dist.x < side_dist.z) {
+        if(side_dist.x < side_dist.y) {
+            vnormal = voxel_pos(-vstep.x, 0, 0);
+            distance = side_dist.x;
+            side_dist.x += delta_dist.x;
+            vpos.x += vstep.x;
+        }
+        else {
+            vnormal = voxel_pos(0, -vstep.y, 0);
+            distance = side_dist.y;
+            side_dist.y += delta_dist.y;
+            vpos.y += vstep.y;
+        }
+    }
+    else {
+        if(side_dist.z < side_dist.y) {
+            vnormal = voxel_pos(0, 0, -vstep.z);
+            distance = side_dist.z;
+            side_dist.z += delta_dist.z;
+            vpos.z += vstep.z;
+        }
+        else {
+            vnormal = voxel_pos(0, -vstep.y, 0);
+            distance = side_dist.y;
+            side_dist.y += delta_dist.y;
+            vpos.y += vstep.y;
+        }
+    }
+
+    // This is slower than I want it to be
+    return dimension->get_voxel(vpos);
+}
+